1. Field of the Invention
The invention relates to a piling machine and a method, and more particularly to a piling machine with a high-pressure jet spiral bit and a piling method.
2. Description of the Related Art
Piling machines are widely used in construction of pile foundation such as buildings, bridges, municipal engineering, water resources, dock projects and so on. For current spiral drills, diameters of all parts thereof are the same except for the drill bits, and for long spiral drills, a length of the spiral portion is the same as that of a pile, which causes large revolving resistance. Therefore, in construction of large-diameter and long piles, high power or decreased piling length and diameter are required, and thus it cannot meet design requirements. For short spiral drills, although the spiral portion is short, several times are required for the drill bits to entirely enter soils and the short spiral drills cannot be used in soft soils. For coastal muddy clay, the spiral drills cannot be used since clay soils are difficult to be cleaned. In driving piles using spiral drills with lead-in pipes, it is difficult to pull the lead-in pipes out and the cost is very high. China patent number ZL200410094076.1 discloses a piling method, comprising pulling soils in a drill hole out from the ground using spiral portions on the spiral drills and then cleaning the soils.
Therefore, the current long and short spiral drills, drills with lead-in pipes, drill holes and piling machines have disadvantages in terms of techniques, carrying capability, cost and so on, especially in geological places such as coastal mud, muddy clay, powdery clay, places difficult in forming retaining walls by fine sands, and sedimentary rocks.